HP TACL - Figure 4-2 Performing a Nowaited Read

Requesting Nowaited Reads
Accessing Files
107365 Tandem Computers Incorporated 4–5
This routine uses #VARIABLEINFO/VARIABLE/ to return a variable name to the
#CASE statement. #VARIABLEINFO/VARIABLE/ returns the name of a variable
without the level number so that it will match one of the labels. The #WAIT built-in
function, when used alone, returns the variable name with the level number.
Figure 4-2. Performing a Nowaited Read
?SECTION nowaited_read ROUTINE
#FRAME
#PUSH open_error read_error read_data read_prompt line
#PUSH read_file rslt
#SET rslt [#ARGUMENT /VALUE read_file/ FILENAME OTHERWISE]
[#CASE [rslt]
|1|
== Open the file:
#SET open_error [#REQUESTER /WAIT/ READ [read_file]
read_error read_data read_prompt]
[#IF [open_error] |THEN|
#OUTPUT *** Error opening [read_file]: [open_error]
#RETURN
]
#SET read_error 0
[#LOOP |WHILE| NOT [read_error] |DO|
#APPEND read_prompt *start*
[#CASE [#VARIABLEINFO/VARIABLE/
[#WAIT read_data read_error]] |THEN|
|read_data |
#EXTRACTV read_data line
#OUTPUTV line
|read_error|
== exit loop
] == end case
] == end loop
|OTHERWISE|
#OUTPUT *** Error: Invalid file ***
#RETURN
] == end #CASE
[#IF read_error = 1 |THEN|
#OUTPUT *** End of file ***
|ELSE|
#OUTPUT *** Error reading [read_file]: [read_error]
]
SINK [#REQUESTER/WAIT/CLOSE read_data]
#UNFRAME